In the H.323 video conference system, each of the terminal equipments in the conference site collects various media type streams through respective multi-media equipments, such as main camera and auxiliary camera. Each of the terminal equipments transmits the collected multiple media type streams to an opposite terminal by a method of one logic channel for one type of media type streams; or the collected multiple media type streams are transmitted to a Multipoint Conference Unit (MCU), then several or all of them are combined into one channel of stream through the MCU and transmitted to the terminal equipments.
After acquiring the multiple media type streams transmitted from the opposite terminal, the terminal equipments require to control the remote multi-media equipment according to playing effect of the multiple media type streams.
The conventional art related to the present invention provides a method for a terminal equipment A to control a mainstream camera of a terminal equipment B based on the H.323 protocol, and the implementing process is shown in FIG. 1. The terminal equipment A and the terminal equipment B establish a connection by a calling establishing message; after the connection is established, the terminal equipment A and the terminal equipment B declare through Capability Set message such as TerminalCapabilitySet message of H.245, that they each have the H.224 capability of supporting remote camera control; an H.224 control channel is established between the terminal equipment A and the terminal equipment B by signaling such like for opening the control channel; the terminal equipment A transmits controlling data to the terminal equipment B through the control channel, and the terminal equipment B operates its mainstream camera according to the controlling data, so as to implement the process that the terminal equipment A controls the mainstream camera of the terminal equipment B.
The conventional art is only applicable to the where the controlling data is transmitted through a controlling channel after a type of media type stream is received through a logical channel, and a terminal equipment having received the controlling data controls corresponding multi-media equipment according to the controlling data. But when some terminal equipment receives multiple media type streams through multiple logical channels and transmits the controlling data through one controlling channel, the some terminal equipment having received the controlling data cannot determine which multiple media type stream corresponds to the controlling data, and hence cannot determine multi-media equipment generating the media type stream to be controlled.
In addition, for joining in the multipoint conference held by the MCU, because the streams sent to the terminal equipment by the MCU correspond to multiple pictures, the terminal equipment cannot determine to which picture the control stream received according to the conventional method corresponds, and hence cannot control the multi-media equipment that generate the stream.